On Wed, Aug 5, 2020 at 12:44 AM John Stultz [off-list ref] wrote:

On Fri, Jul 17, 2020 at 5:06 PM Saravana Kannan [off-list ref] wrote:

quoted

Switch the driver to use the helper macros. In addition to reducing the
number of lines, this also adds module unload protection (if the driver
is compiled as a module) by switching from module_platform_driver to
builtin_platform_driver.

Signed-off-by: Saravana Kannan <redacted>
---
 drivers/irqchip/qcom-pdc.c | 26 +++-----------------------
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
index 5b624e3295e4..c1c5dfad57cc 100644
--- a/drivers/irqchip/qcom-pdc.c
+++ b/drivers/irqchip/qcom-pdc.c

@@ -432,28 +432,8 @@ static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
        return ret;
 }

-static int qcom_pdc_probe(struct platform_device *pdev)
-{
-       struct device_node *np = pdev->dev.of_node;
-       struct device_node *parent = of_irq_find_parent(np);
-
-       return qcom_pdc_init(np, parent);
-}
-
-static const struct of_device_id qcom_pdc_match_table[] = {
-       { .compatible = "qcom,pdc" },
-       {}
-};
-MODULE_DEVICE_TABLE(of, qcom_pdc_match_table);
-
-static struct platform_driver qcom_pdc_driver = {
-       .probe = qcom_pdc_probe,
-       .driver = {
-               .name = "qcom-pdc",
-               .of_match_table = qcom_pdc_match_table,
-               .suppress_bind_attrs = true,
-       },
-};
-module_platform_driver(qcom_pdc_driver);
+IRQCHIP_PLATFORM_DRIVER_BEGIN(qcom_pdc)
+IRQCHIP_MATCH("qcom,pdc", qcom_pdc_init)
+IRQCHIP_PLATFORM_DRIVER_END(qcom_pdc)
 MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Power Domain Controller");
 MODULE_LICENSE("GPL v2");

<sigh>
So this is where I bashfully admit I didn't get a chance to try this
patch series out, as I had success with a much older version of
Saravana's macro magic.

But unfortunately, now that this has landed in mainline, I'm seeing
boot regressions on db845c. :( This is in the non-modular case,
building the driver in.

Does that mean the modular version is working? Or you haven't tried
that yet? I'll wait for your reply before I try to fix it. I don't
have the hardware, but it should be easy to guess this issue looking
at the code delta.

The only significant change from what your probe function is doing is
this snippet. But it'd be surprising if this only affects the builtin
case.

+ if (par_np == np)
+         par_np = NULL;
+
+ /*
+ * If there's a parent interrupt controller and  none of the parent irq
+ * domains have been registered, that means the parent interrupt
+ * controller has not been initialized yet.  it's not time for this
+ * interrupt controller to initialize. So, defer probe of this
+ * interrupt controller. The actual initialization callback of this
+ * interrupt controller can check for specific domains as necessary.
+ */
+ if (par_np && !irq_find_matching_host(np, DOMAIN_BUS_ANY))
+         return -EPROBE_DEFER;

I managed to bisect it down to this patch, and reverting it avoids the
issue. I don't see what is wrong right off, but I really need to get
to bed, so I'll dig further tomorrow.

Saravana: Apologies for not getting around to testing this beforehand!

No worries. Apologies for breaking it accidentally.

-Saravana

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